1. Field of the Invention
The present invention relates to a golf club head. More specifically, the present invention relates to a golf club head having a plurality of grooves.
2. Description of the Related Art
The prior art discloses various methods to manufacture golf club heads, especially iron-type golf club heads. For example, Rogers, U.S. Pat. No. 4,027,885 for Golf Iron Manufacture, discloses scoring grooves into a face for the club head.    Taylor, U.S. Pat. No. 4,077,632 for a Lined Face For A Golf Club discloses grooves in compliance with the Rules of Golf at that time.    Moore, U.S. Pat. No. 4,558,505, for a Method Of Making Weighted Metal Golf Club Head discloses at process for making an iron-type golf club head.    Shira, U.S. Pat. No. 4,768,787, for a Golf Club Including High Friction Striking Face discloses grit blasting the horizontal grooves to provide a friction generating surface when the striking surface of the golf club head engages a ball.    Stuff, U.S. Pat. No. 5,354,059, for Golf Club Heads With Means For Imparting Corrective Action, discloses a club head with at least two non-parallel sets of grooves.    Funk, U.S. Pat. No. 5,487,543, for a Shot Peened Golf Club Head, discloses shot peening the striking surface of a golf club head.    Mogan, U.S. Pat. No. 6,059,670, for a Golf Club Having A Head With A Hard Multilayer Striking Surface And Method For Making The Same, discloses manufacturing a club head by heat treatments, vacuum treatments, and roughening.    Doolen, U.S. Pat. No. 6,179,725, for a Golf Club Having Angular Grooves discloses grooves oriented at various angles.    Hirota, U.S. Pat. No. 6,193,615, for a Head Of Golf Clubs That Spins More, discloses a face having grooves that allow for pressure to act specially on the edges of the grooves to increase ball spin.    Vokey et al, U.S. Pat. No. 7,473,187, for Spin Milled Grooves For A Golf Club, discloses machining grooves into a face.    Hettinger et al., U.S. Pat. No. 7,452,283, for a Putterhead With Dual Milled Face Pattern, discloses milling grooves into a face of a putter.    Kennedy, III, U.S. Pat. No. 7,179,175, for a Golf Club Having Stepped Grooves, discloses a golf club head with V-shaped and U-shaped grooves.
Scoreline designs generally have a cross-section geometry that includes two edges, two side walls and a bottom. The side walls are at a predetermined angle from a vertical line. Usually, each wall has more than one section and those sections are straight or curved. Alternatively, the scoreline design is a “V” shape, in which case there is no bottom other than a vertex or fillet radius.
Iron-type golf clubs having scorelines with sharp edges and relatively vertical side walls are advantageous to golfers since such sharp edged grooves allow golfers to induce higher levels of spin on a ball struck with such an iron-type golf club having sharp edged grooves. Iron-type golf clubs without sharp edged grooves or essentially vertical side walls will induce less spin when impacting a golf ball, especially higher-lofted (40 degrees+) golf clubs.
Backspin is the primary mechanism by which a golfer can control a golf ball upon landing after being struck. Backspin is especially important for short shots where proximity to the hole is of greater consequence to the golfer. High lofted clubs (50 degrees to 75 degrees) have grooves designs which are meant to interact with the surface of a golf ball at impact and remove debris from the contacting surface in order to increase friction and thereby impart more spin on the ball.
Prior irons have scoreline patterns wherein the amount of face area below the bottom scoreline at any position across the face is excessive. This is the result of prior irons having scoreline patterns where the individual scorelines, or grooves, are generally co-linear, or parallel and spaced apart by at least 0.075″. However, since the bottom of an iron face is generally curved, the scorelines are often offset upward from the bottom of the face, perhaps being minimally close to the bottom at one point but substantially further away from the bottom at most points. This leaves a substantial portion of the face near the bottom perimeter with a reduced density of scorelines. Since this portion of the face tends to be hit most often by golfers, the relative scarcity of scorelines in this area can have an adverse effect on the spin imparted to the ball.
The Rules of Golf as interpreted by the United States Golf Association (“USGA”) have constrained the types of scoreline patterns that may be used on golf clubs.